For awhile now I've been compiling pictures of Daisy holding things that match. It's a particular pleasure to her when she finds such things (she especially likes if there's a big one and a little one, but two-just-the-same is also nice) and she always reacts with an excitement that is quite delightful to behold. Even when she could hardly talk, she would say, "Mommy! I match it!" every time she encountered something that (even slightly) resembled something else. Then she'd run to get the counterpart of whatever-it-was---because, obviously, something that matches is no use unless you actually put the things next to each other.
She got the little penguin for Easter, then bought the big penguin with her birthday money from grandma (other candidates for this money were "a rainbow dress" and "a beehive").
Little phonebook, big phonebook
Matching books (she will even remember book designs across library trips, and if we've already returned the "matching" book when she discovers the one that goes with it, it's a sad day)
Big tennis ball, little tennis ball
Big stool, little stool
Penguins wearing backpacks
The mommy and baby beaters are doing a little song and dance
Matching animals in the crocheted purses/bassinets I made a long time ago
It was a happy day when she got to have Goldie be her baby bunny
These monkeys, which had previously been hanging in various locations on the tree, appeared like this one morning---the Mad Matcher strikes again!
If she could dress Marigold to match her every day, she would.
She got the third penguin for Christmas, after having spotted it on a webpage I was looking at one day, and subsequently saying every few hours, "When I grow up I'm going to get a job and then I can buy that tiny blanket-penguin and then I can match him with my other penguins!"